The effect of ambient conditions on the performance of supplementary fired gas-steam combined cycle

The effect of ambient conditions, ambient temperature and site location of the power plant (the altitude or ambient pressure), on the performance of a typical supplementary fired (SF) gas-steam combined cycle (CC) is studied, and its performances are compared with that of the unfired case. The CC used in the present study is comprised of two V94.2 gas turbine units, two HR-stearn generators and a single steam cycle. For the cases studied, it is observed that SF can increase the total net power of the CC by 5% and the efficiency for the fired-cycle is observed to be about 1% less than that of unfired-cycle case. The variations of the total net power with ambient temperature for both supplementary fired and unfired cases (slope w.r.t. the ambient temperature) are almost identical.